In a broad sense, needleless syringes are used for the subcutaneous injection of therapeutic agents. Conventional needleless syringes rely on rapid expansion of a gas to accelerate a flow of the therapeutic agents in particle form. Use of a needleless syringe avoids physically perforating the epidermis. The therapeutic agents can present themselves in powder form. The active substances can be vaccines, anesthetics, medicines, hormones, and genetic compounds, for example. These agents, while in the form of particles whose size is of the order of a few microns to tens of microns, are capable of penetrating the skin of a patient, due to the high velocity imparted upon them.
Conventional needleless syringes may fail to meet some of the required characteristics for such devices. Penetration depth of the therapeutic agents may not be sufficient for some applications. Penetration depth versatility is therefore lacking.
Therefore, there is a need for needleless syringes having improved operational characteristics.